ALZHEIMER'S AMYLOID PLAQUE PERSISTENCE IN VIVO

阿尔茨海默病(AD)是一种退行性脑疾病，临床特征为记忆、认知、推理、判断和情绪稳定性的进行性丧失，逐渐导致严重的精神恶化，最终导致死亡。AD的特征是大脑中含有β-淀粉样蛋白(Abeta)的不溶性纤维淀粉样沉积，要么以细胞外淀粉样斑块的形式存在，要么以脑实质内血管壁的形式存在。Aβ淀粉样蛋白在脑内的持续存在被认为在AD的发病机制中起核心作用，导致神经元丢失和记忆功能障碍。在过去的几年里，我们的研究已经确定了其他额外的因素，如特定的硫酸肝素蛋白多糖(即Perlecan)，对于AD脑中“纤维状”Abeta沉积的形成和持续是必要的。使用纯化的Perlecan为Aβ淀粉样蛋白在脑内的快速沉积和持续存在建立了一致的啮齿动物模型。将Abeta+perlecan注入海马体1或2周后，80只动物中有80只(100%)出现嗜细胞淀粉样蛋白沉积，而单独注射Abeta后，70只动物中有41只(58.5%)出现了嗜中性淀粉样蛋白沉积。Perlecan有助于Abeta淀粉样蛋白在大脑中的长期存在和脑血管淀粉样蛋白沉积的形成，这在Abeta注射后没有观察到。我们现在已经通过实施新的专利方案来显著改进这一动物模型，以诱导体外形成马耳他交叉的同嗜性淀粉样斑样沉积，这种沉积在形态和超微结构上与来自AD脑的淀粉样斑核心相似。新的动物建模方法可用于在体内快速识别潜在的抗淀粉样斑块治疗药物，这些药物针对大脑中的淀粉样斑块a)沉积，b)持久性和/或c)溶解和清除。这一第一阶段提案的主要目标是1)确定蛋白多糖/GAG在淀粉样斑块形成中的作用，以及2)确定“淀粉样斑块”、“纤维”Abeta持续性和脑血管淀粉样蛋白沉积在大脑中的解剖学和分子后果。所描述的研究将进一步建立Abeta淀粉样斑块沉积和持久性的一致动物模型，并将允许(在II期方案中)快速筛选新的潜在治疗候选药物来治疗AD中的Abeta斑块淀粉样变性。拟议的商业应用：阿尔茨海默病(AD)目前影响着400-500万美国人，估计成本为800-1000亿美元。目前，没有治愈或有效的治疗方法，患者通常在发病后3-10年内死亡。迫切需要新的动物模型来快速测试抗Aβ淀粉样蛋白疗法的疗效。我们已经发现了在试管中持续形成阿尔茨海默病淀粉样斑块的新方法，并正在建立一种新的体内淀粉样斑块持续存在的动物模型。该模型可用于未来快速筛选新的抗淀粉样斑块治疗药物。

Alzheimer's disease (AD) is a degenerative brain disorder characterized clinically by progressive loss of memory, cognition, reasoning, judgement and emotional stability that gradually leads to profound mental deterioration and ultimately death. AD is characterized by the brain accumulation of insoluble fibrillar amyloid deposits containing the beta-amyloid protein (Abeta), either as extracellular amyloid plaques or in blood vessel walls in the brain parenchyma. Abeta amyloid persistence in brain is believed to play a central role in AD pathogenesis by contributing to neuronal loss and memory dysfunction. Over the last few years, our studies have determined that other additional factors, such as specific heparan sulfate proteoglycans (i.e. perlecan), are necessary for the formation and persistence of "fibrillar" Abeta deposits in AD brain. Use of purified perlecan has established a consistent rodent model for the rapid deposition, and persistence of Abeta amyloid in brain. 1 or 2- week infusions of Abeta + perlecan into hippocampus leads to congophilic amyloid deposits in 80 of 80 animals (100%), in comparison to 41 of 70 (58.5%) following infusions of Abeta alone. Perlecan contributes to the long- term persistence of Abeta amyloid in brain and the formation of cerebrovascular amyloid deposits, not observed following Abeta infusions. We have now significantly advanced this animal model by implementing new proprietary protocols to induce the in vitro formation of maltese-cross congophilic amyloid plaque-like deposits, which are morphologically and ultrastructurally similar to those amyloid plaque cores derived from AD brain. New animal modeling methodologies can be used for the rapid in vivo identification of potential anti-amyloid plaque therapeutics that target amyloid plaque a) deposition, b) persistence and/or c) dissolution and clearance, in brain. The major objectives of this phase I proposal are 1) to determine the role of proteoglycans/ GAGs on amyloid plaque formation, and 2) to determine anatomical and molecular consequences of "amyloid plaque", "fibrillar" Abeta persistence, and cerebrovascular amyloid deposition in brain. The studies described will further establish a consistent animal model for Abeta amyloid plaque deposition and persistence, and will allow (in a phase II proposal) for the rapid screening of new potential therapeutic candidates to treat Abeta plaque amyloidosis in AD. PROPOSED COMMERCIAL APPLICATIONS: Alzheimer's disease (AD) currently affects 4-5 million Americans, at an estimated costs of $80-$100 billion. Currently, there is no cure or effective treatment, and the patient usually dies within 3-10 years from disease onset. New animal models which can be implemented to rapidly test the efficacy of anti-Abeta amyloid therapeutics are desperately needed. We have discovered new methods to consistently form Alzheimer's amyloid plaque-like deposits in a test tube, and are establishing a new animal model of amyloid plaque persistence in vivo. This model can be utilized to rapidly screen for new anti- amyloid plaque therapeutics in the future.